There are many papers/patents on the synthesis of ketocoumarins of the following type:

The original process for making ketocoumarins was patented in 1954, by Kurt Knoevenagel (GB752528—30 Sep. 1954). Since then there have been various papers and patents describing the synthesis of ketocoumarins.
Eastman Chemical Co.—Tetrahedron, 38(9), 1203-1211 (1982), and U.S. Pat. No. 4,147,552 (2 Feb. 1976), EP0022188 (18 Jun. 1979)—describe the synthesis of both types shown above with various substituents. Eastman is also claiming their use as spectral sensitizers/co-initiators.
The synthesis of 3-aroylcoumarins has also been patented by Perm. Pharmaceutical Institute USSR as SU707197 USSR (21 Sep. 1978).
More recently there has been some process patents filed on more environmentally friendly production such as solvent free syntheses, e.g. Formulation for Scientific Technology Promotion; JP2002179666 (15 Dec. 2000); Grunenthal GmbH WO2004002980 (1 Jul. 2002).
There have also been many papers and patents on the synthesis of ketocoumarins with various functional groups attached, e.g. 3M have a family of patents with a priority date of 25 Oct. 1991 (U.S. Pat. No. 5,480,994, U.S. Pat. No. 5,455,143, EP0538997, U.S. Pat. No. 5,415,976, and U.S. Pat. No. 5,534,633). These patents claim many functional groups but seem to focus mainly on amine functionality.
Many other companies have also patented di-alkyl amino functional materials and their use as photoinitiator sensitizers, e.g. Thiokol Morton Inc., PH26210 and U.S. Pat. No. 4,894,314 (12 Nov. 1986); Toppan Printing, JP3070704 (10 Aug. 1989); Toyo Ink Mfg., JP5230118 and JP2727851 (19 Feb. 1992), JP4145102 (5 Oct. 1990; Eastman, CA1137696 (16 Nov. 1979); Cookson, JP2000869 (4 Dec. 1987); Tokuyama Corp., US2004186195 and EP1431315 (18 Dec. 2002).
Other synthesis patents include, for example: The sulfonation of ketocoumarins, materials used as photoresists—Clariant Int. Ltd., TW518332 and WO9839318 (7 Mar. 1997); Acrylated ketocoumarin—this material is claimed but no example is given on how to make it. LG Chemical Ltd., KR20090108154 (11 Apr. 2008). LG are claiming this type of material as photosensitive photoinitiators.
Ketocoumarin materials with acrylate functional groups have also been made by Ciba (e.g. WO2005014677). The application of the materials in this patent is as sensitizers for liquid crystals.
Examples of prior art related to certain types of ketocoumarins as photoinitiators include: Acrylated ketocoumarin, LG Chemical Ltd., KR20090108154 (11 Apr. 2008). LG are claiming this type of material as a photosensitive photoinitiator; Eastman Chemical Co.—Tetrahedron, 38(9), 1203-1211 (1982), and U.S. Pat. No. 4,147,552 (2 Feb. 1976), EP0022188 (18 Jun. 1979) and JP1048059 (24 Jul. 1987). Eastman claims the use of ketocoumarins as sensitizers in combination with amine functional materials. A huge range of ketocoumarin structures are claimed with various substituents used; National Super Chim Mulhouse—the use of thioxanthones and ketocoumarins as photoinitiators using visible laser light in the presence of amines and onium salts. Journal of Applied Polymer Science, (1992), 44(10), 11779-86; Bulletin des Societes Chimiques Belges, (1990), 99(11-12), 969-975; Surface Active Photoinitiators. Ciba, WO0248204, WO0248203, WO0248202 (13 Dec. 2000). Organopolysiloxanes have photoinitiator groups attached and are concentrated on the surface of the composition to improve cure. These patents outline the synthesis process of various photoinitiator types and the binding of these materials onto organopolysiloxanes and their cure properties. No cure results are reported for the ketocoumarin type materials; Ketocoumarins attached to polysilsesquioxane materials. Useful as low migration photoinitiators. Amine synergist groups are also incorporated. The patent mainly describes other more common PI types and their cure properties. No cure properties are given for the ketocoumarin type materials. Ciba/BASF WO2010063612 and EP2370449 (1 Dec. 2008); Ketocoumarins attached as pendant groups to a polyalkylene oxide. Oxirane functional photoinitiators have been made and attached via an in-situ reaction with alkylene oxides (the alkylene oxides forming linear polymers). The examples given in the patent are for Benzophenones. No examples of ketocoumarins are given but they are in the claims. Coloplast A/S WO2011103878 (23 Feb. 2010).
There are a number of patents which describe the use of certain ketocoumarins as photosensitizers for photopolymerization processes when used in combination with various other materials, e.g. Titanocenes: Hitachi, TW434455, U.S. Pat. No. 5,811,218 and EP0636939 (28 Jul. 1993), JP7271028 (28 Sep. 1993), JP11209613 and JP11209614 (30 Jan. 1998), JP2000258907 (11 Mar. 1999); Mitsui Toatsu Chemicals, JP9227547 (20 Feb. 1996); Ciba-Geigy Corp., U.S. Pat. No. 5,011,755 (2 Feb. 1997).
Maleimides have been used with many different functional ketocoumarins to improve the polymerization of HDDA, for example: Albemarle Corp., Univ. Of Southern Mississippi, WO2004089995 (3 Apr. 2003).
Borates have been used with functional ketocoumarins, for example Toyo Boseki, JP2157760 (10 Dec. 1988).
Imidazoles/Thiols/Amines have been used with functional ketocoumarins, for example Mitsubishi Chem. Ind., JP61123603 (19 Nov. 1984).
Dual cure with cationic photoinitiators and ferrocene have been used with functional ketocoumarins, for example Nippon-Soda, JP7196712 (28 Dec. 1993).
Active halogen compounds such as trihalofunctional triazines or sulfonylchlorides have been used with functional ketocoumarins, for example Fuji Photo Film Co. Ltd., JP58015503 and U.S. Pat. No. 4,505,793 (20 Jul. 1981).
Ketocoumarins have been used as a sensitizer in combination with organic peroxides, triazines, benzophenones, quinones, N-phenyl glycine and alkyl aryl ketones; and used in liquid injection recording head, for example Canon KK, JP4294148 (25 Mar. 1991); Canon KK/Sanyo Chemical Ind., JP63270703 and JP63145304 (9 Dec. 1986).
Amine functional ketocoumarins have been used as sensitizers with iodonium salts and triazine materials, for example 3M family of patents with a priority date of 25 Oct. 1991 (U.S. Pat. No. 5,480,994, U.S. Pat. No. 5,455,143, EP0538997, U.S. Pat. No. 5,415,976, U.S. Pat. No. 5,534,633. These patents focus mainly on amine functional ketocoumarins as sensitizers.
Aminofunctional ketocoumarins have been used as sensitizers with camphorquinone, dialkylaminobenzoates and imidazolyl dimmers, for example Thiokol Morton Inc., PH26210 and U.S. Pat. No. 4,894,314 (12 Nov. 1986).
Amino functional ketocoumarins have been used as sensitizers with diaryliodonium salts and organic peroxides, for example Toppan Printing, JP3070704 (10 Aug. 1989).
Amino functional ketocoumarins have been used as sensitizers with cationic sulfonium salts, for example Toyo Ink Mfg., JP5230118 and JP2727851 (19 Feb. 1992), JP4145102 (5 Oct. 1990.
Amino functional ketocoumarins have been used as sensitizers with phenyl glycine and indoleacetic acid, for example Eastman, CA1137696 (16 Nov. 1979).
Amino functional ketocoumarins have been used as sensitizers with triazine functional materials, for example Cookson, JP2000869 (4 Dec. 1987).
Amino functional ketocoumarins have been used as sensitizers in a dual cure system with sulfonium salts, Iodonium salts and polycyclic aromatic materials, for example Tokuyama Corp., US2004186195 and EP1431315 (18 Dec. 2002).
Ketocoumarins have been used as sensitizers for aromatic-onium salts for adhesives (epoxy/acrylate adhesives). Cured by visible light, for example Toyo Ink Mfg. Co., JP7082546 and JP7082544 (17 Sep. 1993).
Ketocoumarins have been used as photosensitizers with Amino-alkylphenones (Irgacure 369/379 type materials), for example Ciba EP1410109 (and family of patents) (26 Jul. 2001).
A recent patent by Fuji (EP2388146—19 May 2010) on LED curable inks and coatings for offset printing mentions the use of ketocoumarins as sensitizers for some new materials that they have developed (general structure shown below). Their new materials appear to be used as photoinitiators/sensitizers in combination with, in particular, aminoalkylphenones and acylphosphine oxides. There are no claims about the use of coumarins but they are mentioned as possible sensitizers in the main body of the patent.
Other areas where certain types of ketocoumarins have been patented (synthesis and use) are: As dyes/filter dyes and Photoimaging technology, for example Sandoz, GB1509386 (3 Jul. 1974); Hoechst EP0044026 (11 Jul. 1980); ICI, GB1405177 (26 Apr. 1972); Mead Corp., U.S. Pat. No. 4,713,312 and CA1293407 (9 Oct. 1984), JP2191956 (21 Nov. 1988); Brother Ind. Ltd., JP8220746 and JP3185585 (16 Feb. 1995); Nippon Kanko Shikiso Kenkyusho, JP7316147 and JP3554363 (26 May 1995); Konishiroku Photo. Ind., JP2000275827 (29 Mar. 1999).
Ketocoumarins have been used as fluorescent labeling agents, for example Biocarb AB, U.S. Pat. No. 4,956,480 (3 Dec. 1985).
Ketocoumarins have been used in Pharmacological applications, for example Cassella Farbwerke Mainkur AG, GB1014053 (12 Aug. 1961); Hardman and Holden Ltd., GB911632 (7 Sep. 1959); Beecham Group Ltd., GB1307646 (31 Oct. 1969).
None of the prior art references disclose the ketocoumarins of the present invention and their use as described below.